command-mutation.hpp

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/*
  COMMAND-MUTATION.hpp  -  functor encapsulating the actual operation of steam-Command

   Copyright (C)
     2009,            Hermann Vosseler <Ichthyostega@web.de>

  **Lumiera** is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version. See the file COPYING for further details.

*/


#ifndef CONTROL_COMMAND_MUTATION_H
#define CONTROL_COMMAND_MUTATION_H

#include "lib/error.hpp"
#include "steam/control/command-closure.hpp"
#include "steam/control/memento-tie.hpp"



namespace steam {
namespace control {
  namespace err = lumiera::error;
  
  
  class Mutation
    {
      const CmdFunctor func_;
      
    public:
      template<typename SIG>
      Mutation (function<SIG> const& func)
        : func_(func)
        { }
      
      
      
      void
      operator() (CmdClosure& clo)
        {
          if (!clo)
            throw err::State{"Lifecycle error: function arguments not ready"
                            , LERR_(UNBOUND_ARGUMENTS)};
          clo.invoke (func_);
        }
    };
  
  
  
  
  
  
  
  
  
  class UndoMutation
    : public Mutation
    {
      Mutation captureMemento_;
      
    public:
      template<typename SIG, typename MEM>
      UndoMutation (MementoTie<SIG,MEM> & mementoHolder)
        : Mutation (mementoHolder.tieUndoFunc())
        , captureMemento_(mementoHolder.tieCaptureFunc())
        { }
      
      
      Mutation&
      captureState (CmdClosure& clo)
        {
          if (!clo)
            throw err::State{"need additional function arguments to be able to capture UNDO state"
                            , LERR_(UNBOUND_ARGUMENTS)};
          
          captureMemento_(clo);
          return *this;
        }
      
      
    };
  
  
}} // namespace steam::control
#endif